ABSTRACT Support is requested for a Keystone Symposia conference entitled Tumor Metabolism, organized by Drs. Lewis C. Cantley, Karen H. Vousden and Jeffrey A. Engelman. The conference will be held in Keystone, Colorado from February 24-28, 2019. The fact that tumor cells have altered metabolism compared to their tissues of origin has been known for more than 90 years. Some commonly used chemotherapies, such as methotrexate, target metabolic enzymes. Over the past decade there has been a revival of interest in developing new therapies that target metabolic vulnerabilities of tumor cells. Dramatic improvements in technologies for monitoring tumor metabolism by mass spectrometry and by multiple modes of imaging have revealed that tumors evolve diverse alterations in metabolism in order to grow in the primary tissue and in metastatic sites. This conference will bring together scientists with a wide spectrum of expertise who are world leaders in this rapidly moving field. The conference will include talks from pharmaceutical scientists who are developing first in class drugs that target metabolic enzymes. In addition there will be presentations from academic scientists who are studying not only changes in metabolism in tumor cells, but also changes in metabolism in cells in the tumor microenvironment and in the whole body. The conference will also include poster sessions, short talks chosen from poster abstracts and plenty of time for discussion of each talk.